Add function core::iter::zip
This makes it a little easier to `zip` iterators:
```rust
for (x, y) in zip(xs, ys) {}
// vs.
for (x, y) in xs.into_iter().zip(ys) {}
```
You can `zip(&mut xs, &ys)` for the conventional `iter_mut()` and
`iter()`, respectively. This can also support arbitrary nesting, where
it's easier to see the item layout than with arbitrary `zip` chains:
```rust
for ((x, y), z) in zip(zip(xs, ys), zs) {}
for (x, (y, z)) in zip(xs, zip(ys, zs)) {}
// vs.
for ((x, y), z) in xs.into_iter().zip(ys).zip(xz) {}
for (x, (y, z)) in xs.into_iter().zip((ys.into_iter().zip(xz)) {}
```
It may also format more nicely, especially when the first iterator is a
longer chain of methods -- for example:
```rust
iter::zip(
trait_ref.substs.types().skip(1),
impl_trait_ref.substs.types().skip(1),
)
// vs.
trait_ref
.substs
.types()
.skip(1)
.zip(impl_trait_ref.substs.types().skip(1))
```
This replaces the tuple-pair `IntoIterator` in #78204.
There is prior art for the utility of this in [`itertools::zip`].
[`itertools::zip`]: https://docs.rs/itertools/0.10.0/itertools/fn.zip.html
Fixes#80691
When we evaluate a trait predicate, we convert an
`EvaluatedToOk` result to `EvaluatedToOkModuloRegions` if we erased any
regions. We cache the result under a region-erased 'freshened'
predicate, so `EvaluatedToOk` may not be correct for other predicates
that have the same cache key.
This currently creates a field which is always false on GenericParamDefKind for future use when
consts are permitted to have defaults
Update const_generics:default locations
Previously just ignored them, now actually do something about them.
Fix using type check instead of value
Add parsing
This adds all the necessary changes to lower const-generics defaults from parsing.
Change P<Expr> to AnonConst
This matches the arguments passed to instantiations of const generics, and makes it specific to
just anonymous constants.
Attempt to fix lowering bugs
const_evaluatable_checked: Stop eagerly erroring in `is_const_evaluatable`
Fixes#82279
We don't want to be emitting errors inside of is_const_evaluatable because we may call this during selection where it should be able to fail silently
There were two errors being emitted in `is_const_evaluatable`. The one causing the compile error in #82279 was inside the match arm for `FailureKind::MentionsParam` but I moved the other error being emitted too since it made things cleaner imo
The `NotConstEvaluatable` enum \*should\* have a fourth variant for when we fail to evaluate a concrete const, e.g. `0 - 1` but that cant happen until #81339
cc `@oli-obk` `@lcnr`
r? `@nikomatsakis`
Implement (but don't use) valtree and refactor in preparation of use
This PR does not cause any functional change. It refactors various things that are needed to make valtrees possible. This refactoring got big enough that I decided I'd want it reviewed as a PR instead of trying to make one huge PR with all the changes.
cc `@rust-lang/wg-const-eval` on the following commits:
* 2027184 implement valtree
* eeecea9 fallible Scalar -> ScalarInt
* 042f663 ScalarInt convenience methods
cc `@eddyb` on ef04a6d
cc `@rust-lang/wg-mir-opt` for cf1700c (`mir::Constant` can now represent either a `ConstValue` or a `ty::Const`, and it is totally possible to have two different representations for the same value)
Change x64 size checks to not apply to x32.
Rust contains various size checks conditional on target_arch = "x86_64", but these checks were never intended to apply to x86_64-unknown-linux-gnux32. Add target_pointer_width = "64" to the conditions.
Rust contains various size checks conditional on target_arch = "x86_64",
but these checks were never intended to apply to
x86_64-unknown-linux-gnux32. Add target_pointer_width = "64" to the
conditions.
Rollup of 10 pull requests
Successful merges:
- #80189 (Convert primitives in the standard library to intra-doc links)
- #80874 (Update intra-doc link documentation to match the implementation)
- #82376 (Add option to enable MIR inlining independently of mir-opt-level)
- #82516 (Add incomplete feature gate for inherent associate types.)
- #82579 (Fix turbofish recovery with multiple generic args)
- #82593 (Teach rustdoc how to display WASI.)
- #82597 (Get TyCtxt from self instead of passing as argument in AutoTraitFinder)
- #82627 (Erase late bound regions to avoid ICE)
- #82661 (⬆️ rust-analyzer)
- #82691 (Update books)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Apparently #35870 caused a problem in this code (which originally
returned an impl trait) and `#[inline]` was added as a workaround, in
ade79d7609.
The issue is now fixed and the comment and `#[inline]` can now be
removed.
Skip Ty w/o infer ty/const in trait select
Remove some allocations & also add `skip_current_subtree` to skip subtrees with no inferred items.
r? `@eddyb` since marked in the FIXME
Make `Clean` take &mut DocContext
- Take `FnMut` in `rustc_trait_selection::find_auto_trait_generics`
- Take `&mut DocContext` in most of `clean`
- Collect the iterator in auto_trait_impls instead of iterating lazily; the lifetimes were really bad.
This combined with https://github.com/rust-lang/rust/pull/82018 should hopefully help with https://github.com/rust-lang/rust/pull/82014 by allowing `cx.cache.exported_traits` to be modified in `register_res`. Previously it had to use interior mutability, which required either adding a RefCell to `cache.exported_traits` on *top* of the existing `RefCell<Cache>` or mixing reads and writes between `cx.exported_traits` and `cx.cache.exported_traits`. I don't currently have that working but I expect it to be reasonably easy to add after this.
name async generators something more human friendly in type error diagnostic
fixes#81457
Some details:
1. I opted to load the generator kind from the hir in TyCategory. I also use 1 impl in the hir for the descr
2. I named both the source of the future, in addition to the general type (`future`), not sure what is preferred
3. I am not sure what is required to make sure "generator" is not referred to anywhere. A brief `rg "\"generator\"" showed me that most diagnostics correctly distinguish from generators and async generator, but the `descr` of `DefKind` is pretty general (not sure how thats used)
4. should the descr impl of AsyncGeneratorKind use its display impl instead of copying the string?
const_generics: Dont evaluate array length const when handling yet another error
Same ICE as #82009 except triggered by a different error.
cc ``@lcnr``
r? ``@varkor``
Ensure valid TraitRefs are created for GATs
This fixes `ProjectionTy::trait_ref` to use the correct substs. Places that need all of the substs have been updated to not use `trait_ref`.
r? ````@jackh726````
Implement RFC 2580: Pointer metadata & VTable
RFC: https://github.com/rust-lang/rfcs/pull/2580
~~Before merging this PR:~~
* [x] Wait for the end of the RFC’s [FCP to merge](https://github.com/rust-lang/rfcs/pull/2580#issuecomment-759145278).
* [x] Open a tracking issue: https://github.com/rust-lang/rust/issues/81513
* [x] Update `#[unstable]` attributes in the PR with the tracking issue number
----
This PR extends the language with a new lang item for the `Pointee` trait which is special-cased in trait resolution to implement it for all types. Even in generic contexts, parameters can be assumed to implement it without a corresponding bound.
For this I mostly imitated what the compiler was already doing for the `DiscriminantKind` trait. I’m very unfamiliar with compiler internals, so careful review is appreciated.
This PR also extends the standard library with new unstable APIs in `core::ptr` and `std::ptr`:
```rust
pub trait Pointee {
/// One of `()`, `usize`, or `DynMetadata<dyn SomeTrait>`
type Metadata: Copy + Send + Sync + Ord + Hash + Unpin;
}
pub trait Thin = Pointee<Metadata = ()>;
pub const fn metadata<T: ?Sized>(ptr: *const T) -> <T as Pointee>::Metadata {}
pub const fn from_raw_parts<T: ?Sized>(*const (), <T as Pointee>::Metadata) -> *const T {}
pub const fn from_raw_parts_mut<T: ?Sized>(*mut (),<T as Pointee>::Metadata) -> *mut T {}
impl<T: ?Sized> NonNull<T> {
pub const fn from_raw_parts(NonNull<()>, <T as Pointee>::Metadata) -> NonNull<T> {}
/// Convenience for `(ptr.cast(), metadata(ptr))`
pub const fn to_raw_parts(self) -> (NonNull<()>, <T as Pointee>::Metadata) {}
}
impl<T: ?Sized> *const T {
pub const fn to_raw_parts(self) -> (*const (), <T as Pointee>::Metadata) {}
}
impl<T: ?Sized> *mut T {
pub const fn to_raw_parts(self) -> (*mut (), <T as Pointee>::Metadata) {}
}
/// `<dyn SomeTrait as Pointee>::Metadata == DynMetadata<dyn SomeTrait>`
pub struct DynMetadata<Dyn: ?Sized> {
// Private pointer to vtable
}
impl<Dyn: ?Sized> DynMetadata<Dyn> {
pub fn size_of(self) -> usize {}
pub fn align_of(self) -> usize {}
pub fn layout(self) -> crate::alloc::Layout {}
}
unsafe impl<Dyn: ?Sized> Send for DynMetadata<Dyn> {}
unsafe impl<Dyn: ?Sized> Sync for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Debug for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Unpin for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Copy for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Clone for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Eq for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> PartialEq for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Ord for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> PartialOrd for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Hash for DynMetadata<Dyn> {}
```
API differences from the RFC, in areas noted as unresolved questions in the RFC:
* Module-level functions instead of associated `from_raw_parts` functions on `*const T` and `*mut T`, following the precedent of `null`, `slice_from_raw_parts`, etc.
* Added `to_raw_parts`
- Take `FnMut` in `rustc_trait_selection::find_auto_trait_generics`
- Take `&mut DocContext` in most of `clean`
- Collect the iterator in auto_trait_impls instead of iterating lazily; the lifetimes were really bad.
- Changes `fn sess` to properly return a borrow with the lifetime of `'tcx`, not the mutable borrow.
Suggest to create a new `const` item if the `fn` in the array is a `const fn`
Fixes#73734. If the `fn` in the array repeat expression is a `const fn`, suggest creating a new `const` item. On nightly, suggest creating an inline `const` block. This PR also removes the `suggest_const_in_array_repeat_expressions` as it is no longer necessary.
Example:
```rust
fn main() {
// Should not compile but hint to create a new const item (stable) or an inline const block (nightly)
let strings: [String; 5] = [String::new(); 5];
println!("{:?}", strings);
}
```
Gives this error:
```
error[E0277]: the trait bound `std::string::String: std::marker::Copy` is not satisfied
--> $DIR/const-fn-in-vec.rs:3:32
|
2 | let strings: [String; 5] = [String::new(); 5];
| ^^^^^^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `String`
|
= note: the `Copy` trait is required because the repeated element will be copied
```
With this change, this is the error message:
```
error[E0277]: the trait bound `String: Copy` is not satisfied
--> $DIR/const-fn-in-vec.rs:3:32
|
LL | let strings: [String; 5] = [String::new(); 5];
| ^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `String`
|
= help: moving the function call to a new `const` item will resolve the error
```
Use debug log level for developer oriented logs
The information logged here is of limited general interest, while at the
same times makes it impractical to simply enable logging and share the
resulting logs due to the amount of the output produced.
Reduce log level from info to debug for developer oriented information.
For example, when building cargo, this reduces the amount of logs
generated by `RUSTC_LOG=info cargo build` from 265 MB to 79 MB.
Continuation of changes from 81350.
